Method for manufacturing a printed circuit board with a thin film capacitor embedded therein having a dielectric film by using laser lift-off, and printed circuit board with a thin film capacitor embedded therein manufactured thereby

ABSTRACT

A method for manufacturing a printed circuit board with a capacitor embedded therein which has a dielectric film using laser lift off, and a capacitor manufactured thereby. In the method, a dielectric film is formed on a transparent substrate and heat-treated. A first conductive layer is formed on the heat-treated dielectric film. A laser beam is irradiated onto a stack formed, from below the transparent substrate, to separate the transparent substrate from the stack. After the transparent substrate is separated from the stack, a second conductive layer is formed with a predetermined pattern on the dielectric film. Also, an insulating layer and a third conductive layer are formed on the first and second conductive layers to alternate with each other in a predetermined number.

CLAIM OF PRIORITY

This application claims the benefit of Korean Patent Application No.2006-67188 filed on Jul. 19, 2005 in the Korean Intellectual PropertyOffice, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for manufacturing a printedcircuit board with a thin film capacitor embedded therein using laserlift-off, and more particularly, to a method for manufacturing a printedcircuit board with a thin film capacitor embedded therein which has adielectric film using laser lift off, and a printed circuit board with athin film capacitor embedded therein manufactured thereby.

2. Description of the Related Art

With a smaller, lighter, higher-speed and higher-frequency trend ofelectronic devices, the electronic devices are increasingly required topossess higher-density. In reality, vigorous studies have been conductedon technologies to integrate passive and/or active devices into asubstrate. Also, in ongoing researches to reduce size of the electronicdevices, many passive devices such as a resistor, a capacitor and aninductor are embedded in a printed circuit board (PCB) instead of beinginstalled thereon. Out of these passive devices, the capacitor accountsfor a considerable proportion of about 60%. Thus, much attention isdrawn on an embedded capacitor. As described above, the capacitor isembedded in the PCB instead of being installed thereon. This downscalessize of the passive device by 40% and assures better electricalproperties at a higher frequency due to low impedance (<10 pH).

The conventional embedded capacitor is disclosed in U.S. Pat. No.5,261,153. The document teaches a method for manufacturing a printedcircuit board with a capacitor embedded therein by lamination ofconductive foils and uncured dielectric sheets alternating therewith.Moreover, U.S. Pat. No. 6,541,137 discloses a high temperature thin filmembedded capacitor using dielectrics. Specifically, the documentproposes a barrier layer for preventing the conductive layer fromoxidizing from high temperature heat treatment of 400° C.□ to 800° C.

However, in this embedded capacitor, a dielectric film is necessarilymade of a dielectric material having a high dielectric constant selectedfrom a group consisting of barium strontium titanate (BSTO), bariumtitanate (BT), lead zirconium titanate (PZT), barium zirconium titanate(BZTO), and tantalum titanate (TTO). This dielectric material should beexcellent in crystallinity to exhibit high dielectric constant. To thisend, the dielectric material should be heat-treated at a temperature of500° C. or more.

But in the conventional embedded capacitor, a thin film is formed on anelectrode as an RCC type and crystallized through heat treatment toimpart a certain dielectric constant to a capacitor product. Then thesematerials are employed in a PCB process. However, the materials needheat-treating at a high temperature of 400° C. to 800° C., and arehardly configured on a resin-containing PCB.

Dielectric properties of the thin film capacitor are greatly affected bythe type of the substrate, as is apparent from FIG. 1. FIG. 1demonstrates capacitance of a Pb-based dielectric film deposited on twotypes of substrates with respect to a voltage applied. A copper foil anda Pt/Ti/SiO₂/Si substrate are adopted for the substrates, and heattreated in the air at 650° C. for 30 minutes. The dielectric film isdeposited to a thickness of 0.6 micrometer. The dielectric film on thecooper foil exhibits capacitance of 0.2 μF/cm², much lower than thedielectric film on the Pt/Ti/SiO₂/Si substrate whose capacitance is 2.5μF/cm². The dielectric film deposited on the copper foil is affected byan oxidized interface resulting from oxidation of the copper foil whichis heat-treated along with the substrate. This prevents the dielectricfilm on the copper foil from manifesting properties peculiar to thedielectric material.

Therefore, studies have been conducted unceasingly to prevent the copperfoil from oxidization in two methods. That is, a heat-treatmentatmosphere has been regulated or a strong oxidation-resistant nickellayer has been formed on the copper foil to deposit and heat-treat thedielectric film. These methods however entail a problem of decreasedcapacitance of the capacitor manufactured.

As a result, there has arisen a demand for developing a method formanufacturing a capacitor with a printed circuit board embedded thereinhaving a dielectric film that needs heat-treating at a high-temperaturethrough a general PCB manufacturing process.

SUMMARY OF THE INVENTION

The present invention has been made to solve the foregoing problems ofthe prior art and therefore an aspect of the present invention is toprovide a method for manufacturing a printed circuit board with acapacitor embedded therein having a dielectric film using laserlift-off, and a printed circuit board with a thin film capacitorembedded therein manufactured thereby.

According to an aspect of the invention, the invention provides a methodfor manufacturing a printed circuit board with a thin film capacitorembedded therein, the method including:

forming a dielectric film on a transparent substrate and heat-treatingthe dielectric film;

forming a first conductive layer on the heat-treated dielectric film;

irradiating a laser beam onto a stack formed, from below the transparentsubstrate, to separate the transparent substrate from the stack;

after the transparent substrate is separated from the stack, forming asecond conductive layer with a predetermined pattern on the dielectricfilm; and

forming an insulating layer and a third conductive layer on the firstand second conductive layers to alternate with each other in apredetermined number.

According to another aspect of the invention, the invention provides amethod for manufacturing a printed circuit board with a thin filmcapacitor embedded therein, the method including:

forming a dielectric film on a transparent substrate and heat-treatingthe dielectric film;

forming a first conductive layer on the heat-treated dielectric film;

forming an insulating layer on the conductive layer and stacking acopper clad laminate on the insulating layer;

irradiating a laser beam onto a stack formed, from below the transparentsubstrate, to separate the transparent substrate from the stack; and

after transparent substrate is separated from the stack, forming asecond conductive layer with a predetermined pattern on the dielectricfilm.

According to further another aspect of the invention, the inventionprovides a method for manufacturing a printed circuit board with a thinfilm capacitor embedded therein, the method including:

forming a dielectric film on a transparent substrate and heat-treatingthe dielectric film;

forming a first conductive layer on the heat-treated dielectric film;

stacking a resin coated copper on the conductive layer;

irradiating a laser beam onto a stack formed, from below the transparentsubstrate, to separate the transparent substrate from the stack;

after the transparent substrate is separated from the stack, forming asecond conductive layer with a predetermined pattern on the dielectricfilm; and

forming an insulating layer and a third conductive layer on the RCC filmand the second conductive layer to alternate with each other in apredetermined number.

According to further another aspect of the invention, the inventionprovides a printed circuit board with a thin film capacitor embeddedtherein manufactured as described above.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a graph illustrating capacitance of a Pb-based dielectric filmformed on a copper foil coated with a nickel oxidation prevention layerand a dielectric film formed on a Pt/Ti/SiO₂/Si substrate, respectively;

FIG. 2 is a view illustrating a method for manufacturing a printedcircuit board with a thin film capacitor embedded therein according toan embodiment of the invention;

FIG. 3 is a view illustrating a method for manufacturing a printedcircuit board with a thin film capacitor embedded therein according toanother embodiment of the invention;

FIG. 4 is a view illustrating a method for manufacturing a printedcircuit substrate with a thin film capacitor embedded therein accordingto further another embodiment of the invention;

FIG. 5 is a graph illustrating dielectric properties of a PZT filmtransferred onto a PCB by excimer laser lift-off;

FIG. 6 is a graph illustrating a X-ray diffraction analysis of adielectric film deposited on a copper foil, a dielectric film depositedon a sapphire, and a PZT thin film transferred onto a polymer/CCLmaterial by excimer laser lift-off, respectively;

FIG. 7 is a TEM picture illustrating a cross-section of a PZT thin filmtransferred onto a polymer/CCL material by excimer laser lift-off, whichhas a laser-induced amorphous layer and a dielectric layer formedthereon;

FIG. 8 is a TEM picture illustrating a cross-section of a PZT thin filmtransferred onto a polymer/CCL material by Femto laser lift-off, inwhich the PZT film maintains a tetragonal crystal structure even afterlaser irradiation; and

FIG. 9 is a graph illustrating dielectric properties of a PZT thin filmtransferred onto a PCB by Femto laser lift-off.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Exemplary embodiments of the present invention will now be described indetail with reference to the accompanying drawings.

FIG. 2 is a schematic view illustrating a method for manufacturing aprinted circuit board with a thin film capacitor embedded thereinaccording to an embodiment of the invention.

As shown in FIG. 2( a), according to the invention, first, alaser-transmissible transparent substrate 11 is prepared, and then adielectric film 13 is formed thereon. In this invention, a material forthe transparent substrate 11 is not limited to a specific type. But thetransparent substrate 11 is made of preferably one selected from a groupconsisting of sapphire, quartz, glass, MgO, lanthanum aluminate(LaAlO₃), fused silica, and zirconia (YSZ).

Also, according to the invention, the dielectric film 13 may be formedby a general sol-gel process using a metal organic precursor exhibitingsuperior dielectric properties by high-temperature heat treatment.Meanwhile, according to the invention, the dielectric film 13 hasvarious dielectric compositions exhibiting superior dielectricproperties through high-temperature heat treatment. However, thedielectric film 13 is not limited to a specific composition and type.For example, the dielectric film 13 can be made of a dielectric materialcontaining volatile elements of e.g., Bi or Pb which is selected from agroup consisting of lead zirconium titanate (PZT), barium titanate (BT),strontium bismuth tantalate (SBT), bismuth lanthanum titanate (BLT),lead magnesium niobate-lead titanate (PMN-PT), and lead zincniobate-lead titanate (PZN-PT), or a dielectric material having a dopantadded thereto.

Next, according to the invention, the dielectric film 13 is heattreated. The heat-treatment improves crystallinity of the thin film andassures superior dielectric properties thereof. Preferably, thedielectric film 13 is heat treated at a temperature of 400° C. or more,and more preferably, at a temperature ranging from 500° C. to 700° C.

Thereafter, according to the invention, as shown in FIG. 2( b), a firstmetal conductive layer 15 is formed on the heat-treated dielectric film13 to serve as an electrode of the thin film capacitor. The conductivelayer 15 may be composed of various conductive metals or oxidants.Preferably, the conductive layer 15 is made of one selected from a groupconsisting of, for example, Au, Ag, Ni, Cu, Al, Pt, Ti, Ir, IrO₂, Ru andRuO₂. Moreover, the first conductive layer 15 can be formed by a generalprocess selected from a group consisting of PVD, CVD, ALD, screenprinting, plating and inkjet printing. Preferably, the first conductivelayer 15 is formed by the PVD using sputtering or e-beam. Morepreferably, the first conductive layer 15 is formed by sputtering.Alternatively, the first conductive layer 15 may be formed by forming ametal seed layer by PVD and electrolytically plating the metal seedlayer.

According to the invention, optionally, the first conductive layer 15may have a predetermined pattern. In order to form this pattern, thefirst conductive layer 15 is formed via a mask by a process selectedfrom PVD, CVD, ALD, screen printing, plating and inkjet printing.Alternatively, a sensitive film is applied on the first conductive layerby a predetermined process, and then the pattern is attained by ageneral process of exposure and development.

Furthermore, according to the invention, a bonding layer or a barrierlayer may be disposed between the dielectric film 13 and the firstconductive layer 15. This ensures the dielectric film 13 and the firstconductive layer 15 to be more bonded together or prevents the firstmetal conductive layer 15 from diffusion and oxidization. Such a bondinglayer or barrier layer can be formed by sputtering Ti or Cr.

Also, according to the invention, as shown in FIG. 2( c), a laser beamis irradiated onto a stack formed, from below the transparent substrate11, to separate the transparent substrate 11 from the stack. That is,the laser beam irradiated from below the transparent substrate 11locally increases temperature of an interface between the substrate 11and the dielectric film 13. This renders some portions of the dielectricfilm elements volatile, thus allowing the substrate 11 to be effectivelyseparated from the dielectric film 13. For example, in a case where adielectric film having a composition of Pb-based PbZrTiO₃ (110/52/48) isdeposited on the sapphire substrate, an excimer laser beam (248 nm) maybe irradiated onto an interface between the PZT thin film and thesapphire substrate at an intensity of 400 mJ/cm². This increasestemperature of the interface between the substrate and the dielectricfilm to at least 1350° C., which is higher than a melting point of PZT.Thus volatile PbO elements are formed at the interface between thesubstrate and the dielectric film, leading to separation of thetransparent substrate 11 from the dielectric film 13.

This invention is not limited to a specific type of the laser and anirradiation method. For example, an excimer laser (126 nm, 146 nm, 157nm, 172 nm, 175 nm, 193 nm, 248 nm, 282 nm, 308 nm, 351 nm, 222 nm, and259 nm) can be adopted to separate the substrate 11 as described above.Alternatively, an Nd YAG laser (266 nm, 355 nm) may be employed. The NdYAG laser has a wavelength corresponding to the energy band gap betweena dielectric film and a transparent substrate. That is, various types oflasers can be utilized to separate the substrate as long as the laserenergy that passed the transparent substrate is absorbed in thedielectric film to increase temperature of the interface between thedielectric film and the substrate to at least a melting point of thedielectric film. A laser beam used at this time can be modified intovarious beam profiles such as spot, square and line.

Meanwhile, when the substrate 11 is separated by an excimer laser or anNd YAG laser, a portion of the dielectric film 13 adjacent to thesubstrate 11, which is exposed to heat of the laser, may have atransformation from a crystalline into an amorphous structure to a smallthickness (about 108 nm), thus producing a damaged layer. This damagedlayer may degrade dielectric properties of the dielectric film. Forexample, the PZT film transferred onto a PCB may have a dielectricconstant ranging from 1 MHz to 600 MHz. However, the PZT film with thisdamaged layer can provide a higher capacitance than the PZT film formedon the copper foil, and thus be suitably applied.

But to ensure much better dielectric properties, preferably, the damagedlayer should be removed. The damaged layer can be removed by variousprocesses such as wet etching and ion beam milling, without beinglimited to a specific process.

To preclude a possibility of the damaged layer, preferably a Femto laserbeam is irradiated onto the stack, from below the substrate, to separatethe transparent substrate 11 from the stack. For example, the Femtolaser beam (800 nm, 300 fs), when employed to separate the substrate 11,can effectively prevent formation of the damaged layer caused by laserirradiation. Inconsequence, the PZT film transferred onto the PCBmanufactured as described above maintains a tetragonal crystalstructure, thereby exhibiting a superior dielectric constant rangingfrom 1 MHz to 1600 MHz.

Next, as shown in FIG. 2( d), after the transparent substrate 11 isseparated from the stack, a second metal conductive layer 17 with apredetermined pattern is formed on the dielectric film 13 to serve asanother electrode. This second conductive layer 17 may be made ofvarious conductive metals or oxidants. Preferably, the second conductivelayer 17 is made of one selected from a group consisting of Au, Ag, Ni,Cu, Al, Pt, Ti, Ir, IrO₂, Ru, and RuO₂. Also, the second conductivelayer 17 is formed by a general process selected from a group consistingof PVD, CVD, ALD, screen printing, plating and inkjet printing.Preferably, the second conductive layer 17 is formed by the PVD usingsputtering or e-beam, and more preferably, sputtering. Alternatively,the second conductive layer 17 is formed by forming a metal seed layerby the PVD and electorlytically plating the metal seed layer.

The second metal conductive layer 17 may be formed to have apredetermined pattern via a mask using the PVD. Alternatively, asensitive film is applied on the first conductive layer by apredetermined process, and then the pattern is attained by a generalprocess of exposure and development.

Subsequently, according to the invention, an insulating layer and athird conductive layer are formed on the first and second conductivelayers to alternate with each other in a predetermined number byadopting a typical manufacturing method of a printed circuit board. Thisproduces a printed circuit board with a dielectric thin fin filmcapacitor embedded therein.

FIG. 3 is a schematic view illustrating a method for manufacturing aprinted circuit board with a thin film capacitor embedded thereinaccording to another embodiment of the invention.

As shown in FIG. 3( a), according to the invention, a dielectric film 23is formed on a transparent substrate 21 and heat-treated. As shown inFIG. 3( b), a first metal conductive layer 25 is formed on theheat-treated dielectric film 23 to serve as an electrode of thecapacitor. Optionally, this first conductive layer 25 has apredetermined pattern. The composition, forming method and patterning ofthe first conductive layer 25 have been described above and thus will beexplained in no more detail.

Also, as described above, a bonding layer or a barrier layer may beformed between the dielectric film 23 and the first conductive layer 25to improve bonding therebetween and prevent the first metal conductivelayer 25 from diffusion or oxidization.

Afterwards, according to the invention, as shown in FIG. 3( c), aninsulating layer 26 is stacked on the conductive layer 25. Theinsulating layer is typically composed of a polymer resin but can bemade of various insulating materials used in a PCB manufacturingprocess.

Moreover, according to the invention, a copper clad laminate (CCL) 27 isstacked on the insulating layer 26. The CCL 27 has an insulating member27 b attached with copper foils 27 a at both surfaces thereof.

Next, as shown in FIG. 3( d), a laser beam is irradiated onto a stackformed, from below the transparent substrate 21, to separate thetransparent substrate 21 from the stack. An explanation has been givenpreviously about a process for separating the transparent substratethrough a laser beam, and type of the laser and subsequent operations,which thus will be explained in no more detail.

Moreover, as shown in FIG. 3( e), after the transparent substrate 21 isseparated from the stack, a second conductive layer 29 with apredetermined pattern is formed on the dielectric film 23 under the sameconditions as described above. This second metal conductive layer 29serves as an electrode of the thin film capacitor. Here, the compositionand forming method of the metal conductive layer 29 have been describedabove and thus will not be explained further.

Thereafter, according to the invention, an insulating layer and a thirdconductive layer are formed on the CCL 27 and the conductive layer 29 toalternate with each other in a predetermined number by adopting ageneral manufacturing method of a printed circuit board.

Meanwhile, FIG. 4 is a schematic view illustrating a method formanufacturing a printed circuit board with a thin film capacitorembedded therein according to further another embodiment of theinvention.

As shown in FIG. 4( a), a dielectric film 33 is formed on a transparentsubstrate 31 and heat-treated. Then as shown in FIG. 4( b), a firstmetal conductive layer 35 is formed on the heat-treated dielectric film33 to serve as an electrode of the capacitor. Optionally, the firstconductive layer 35 has a predetermined pattern. The composition andforming method of the conductive layer 35 have been described above andthus will be explained in no more detail.

Furthermore, as described above, a bonding layer or a barrier layer maybe formed between the dielectric film 33 and the first conductive layer35 to improve bonding therebetween and prevent the first metalconductive layer 35 from diffusion and oxidization.

According to the invention, as shown in FIG. 4( c), a resin coatedcopper (RCC) 37 is stacked on the first conductive layer 35. The RCC hasa copper foil 37 a attached with a resin 37 b.

Then, as shown in FIG. 4( d), a laser beam is irradiated onto a stackformed, from below the transparent substrate 31, to separate thetransparent substrate 31 from the stack. An explanation has been givenpreviously about a process of separating the transparent substrate by alaser beam, and type of the laser and subsequent operations, which thuswill not be explained further.

Also, as shown in FIG. 4( e), after the transparent substrate 31 isseparated from the stack, a second conductive layer 39 with apredetermined pattern is formed on the dielectric film 33 under the sameconditions as described above.

Thereafter, according to the invention, an insulating layer and aconductive layer are formed on the RCC 37 and the second conductivelayer 39 to alternate with each other in a predetermined number by ageneral manufacturing method of a printed circuit board. This produces aprinted circuit board with a dielectric film capacitor embedded therein.

As described above, the printed circuit board with a thin film capacitorembedded therein has a dielectric film using laser lift-off and can bemanufactured effectively in a general PCB manufacturing process.

The invention will be explained in detail by way of example.

EXAMPLE

A dielectric material of PbZrTiO₃ (Zr/Ti=52/48, 10% Pb excess) was spincoated on a sapphire transparent substrate at a thickness of 0.4micrometer by general sol-gel, and heat-treated in the air at atemperature of 650° C. This produced a crystallized PZT dielectric filmon the transparent sapphire substrate. Then, a first Au metal layer wasformed on the dielectric film by sputtering and an insulating layer madeof an epoxy resin was formed on the conductive layer.

Thereafter, a copper clad laminate was disposed on the insulating layerand lamination was performed. Then, an excimer laser beam (308 nm) wasirradiated onto a stack formed, from below the transparent sapphiresubstrate, to separate the transparent substrate from the stack. Here,the excimer laser beam was shaped as a line and had an energy of 400mJ/cm² (308 nm). The laser beam had a size of 370 mm×400 μm, and wasirradiated at a repetition rate of 10 Hz and for a pulse duration of 30nsec. Also, after the transparent substrate was separated from thestack, a second Au conductive layer was formed by sputtering on the PZTdielectric film. This produced a capacitor with a structure of metalconductive layer/dielectric film/metal conductive layer.

FIG. 5 is a graph illustrating change in dielectric constant of a thinfilm capacitor embedded in the PCB substrate manufactured as above withrespect to a frequency. As shown in FIG. 5, the PZT film transferredonto the PCB exhibits a dielectric constant ranging from 1 MHz to 600MHz. Also, the PZT film assures a high capacitance of 1.3 μF/cm² (filmthickness 0.4 micrometer), much higher than 0.2 μF/cm² to 0.3 μF/cm²(FIG. 1) which is obtained from a ferroelectric film on a copper foil.

FIG. 6 is a graph illustrating an x-ray diffraction pattern of a PZTdielectric film (0.6 micrometer). In FIG. 6, A indicates XRD of a PZTfilm on a copper foil, B indicates XRD of a PZT film deposited on asapphire substrate, and C indicates XRD of a PZT film on a sapphiresubstrate transferred onto ABF/CCL by laser lift-off. Here,heat-treatment was performed in the air at a temperature of 650° C. andfor 30 minutes.

As noted from FIG. 6, the PZT film on the copper foil is degraded incrystallinity due to decline in interface properties resulting fromoxidation of the copper foil. In contrast, the PZT film on the sapphiresubstrate exhibits very good crystallinity. Also, the PZT filmtransferred by laser lift off shows a similar XRD pattern, maintaininggood crystallinity.

To determine changes in the PZT films irradiated with laser beam,cross-sections of the PZT films that underwent laser lift-off wereobserved with a transmission electron microscope (TEM), whose resultsare illustrated in FIG. 7. As shown in FIG. 7, a PZT film is constructedof two layers (layer 1 and layer 2) after being irradiated with laserbeam. The layer 1 is a laser-damaged layer with a thickness of about 108nm. The layer 1 features a diffused ring, which is characteristic of anamorphous phase, in the electron diffraction pattern. The layer 1 wasobserved to be amorphous in the high resolution TEM image. Meanwhile,the layer 2 inside the PZT film was observed to have an electrondiffraction pattern indicative of a tetragonal crystal structure. Thelayer 2 also exhibited a tetragonal crystal structure in the highresolution TEM image.

Due to presence of this amorphous layer, as shown in FIG. 7, the PZTthin film transferred onto the PCB according to the invention showed adielectric constant ranging from 1 MHz to 600 MHz, lower than that (1600to 1700) of a general PZT film. Here, the PZT thin film was amorphous.

However, in this invention, this amorphous damaged layer is removed byvarious methods such as wet etching and ion beam milling, therebyelevating its dielectric constant to from 1600 to 1700.

Meanwhile, a capacitor with a structure of a metal conductivelayer/dielectric layer/metal conductive layer was formed under the sameconditions as described above except that the sapphire substrate wasseparated by a Femto laser (800 nm, 300 fs). Moreover, to determinechanges in the PZT films irradiated with laser beam, cross-sections ofthe PZT films that underwent laser lift-off were observed with atransmission electron microscope (TEM), the pictures of which are shownin FIG. 8. As seen from FIG. 8, in a case where the sapphire substratewas separated by a Femto laser, the PZT films obtained had tetragonalcrystal structures, thereby maintaining crystallinity of the PZTmaterial.

FIG. 9 is a graph illustrating a dielectric constant of a PZT filmtransferred onto a PCB substrate using a Femto laser with respect to afrequency. The PZT film exhibits a superior dielectric constant rangingfrom 1 MHz to 1600 MHz.

As set forth above, according to exemplary embodiments of the invention,a printed circuit board with a thin film capacitor embedded therein hasa dielectric film using laser lift off without obstructing a general PCBprocess. In addition, the invention overcomes a conventional problem ofoxidation of a copper foil.

While the present invention has been shown and described in connectionwith the preferred embodiments, it will be apparent to those skilled inthe art that modifications and variations can be made without departingfrom the spirit and scope of the invention as defined by the appendedclaims.

1. A method for manufacturing a printed circuit board with a thin filmcapacitor embedded therein, the method comprising: forming a dielectricfilm comprising one dielectric composition selected from a groupconsisting of lead zirconium titanate, barium titanate, strontiumbismuth tantalate, bismuth lanthanum titanate, lead magnesiumniobate-lead titanate, and lead zinc niobate-lead titanate on atransparent substrate to form a capacitor and heat-treating thedielectric film to improve crystallinity of the dielectric film; forminga first conductive layer on the heat-treated dielectric film;irradiating a laser beam onto a stack formed, from below the transparentsubstrate, to form volatile elements in the dielectric film andtransform the structure of the dielectric film from a crystallinestructure into an amorphous structure; separating the transparentsubstrate from the dielectric film; after the transparent substrate isseparated from the stack, forming a second conductive layer with apredetermined pattern on the dielectric film; after separating thetransparent substrate, removing an amorphous damaged layer formed on atop surface of the dielectric film, which is caused by heat of thelaser; and forming an insulating layer and a third conductive layer onthe first and second conductive layers to alternate with each other in apredetermined number.
 2. The method according to claim 1, wherein thetransparent substrate comprises one selected from a group consisting ofsapphire, quartz, glass, MgO, lanthanum aluminate, fused silica, andzirconia.
 3. The method according to claim 1, wherein the dielectricfilm further comprises a dopant added to the dielectric composition. 4.The method according to claim 1, wherein at least one of the first,second and third conductive layers comprises one selected from a groupconsisting of Au, Ag, Ni, Cu, Al, Pt, Ti, Ir, IrO₂, Ru, and RuO₂.
 5. Themethod according to claim 1, wherein at least one of the first, secondand third conductive layers is formed by a process selected from a groupconsisting of PVD, CVD, ALD, screen printing and inkjet printing.
 6. Themethod according to claim 5, wherein at least one of the first, secondand third conductive layers is formed by the PVD using sputtering ore-beam.
 7. The method according to claim 1, wherein at least one of thefirst, second and third conductive layers is formed by forming a metalseed layer by PVD and electrolytically plating the metal seed layer. 8.The method according to claim 1, wherein the transparent substrate isseparated from the stack by an excimer laser or an Nd YAG laser.
 9. Themethod according to claim 1, wherein the transparent substrate isseparated from the stack by a Femto laser.
 10. The method according toclaim 1, further comprising: after forming the dielectric film, forminga bonding layer or a barrier layer on the dielectric film.
 11. Themethod according to claim 10, wherein the step of forming the bondinglayer or the barrier layer comprises sputtering Ti or Cr.
 12. A printedcircuit board with a thin film capacitor embedded therein manufacturedas described in claim 1.